A possible mechanism for magnetar soft X-ray/γ-ray emission  

作　　者：高志福 彭秋和 王娜 邹志刚 

机构地区：[1]Xinjiang Astronomical Observatory,Chinese Academy of Sciences [2]Key Laboratory of Radio Astronomy,Chinese Academy of Sciences [3]Graduate University of the Chinese Academy of Sciences [4]Department of Astronomy,Nanjing University [5]National Astronomical Observatories,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2012年第5期542-554,共13页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.10773005);the National Basic Research Program of China(Grant No.2009CB824800);the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KJCX 2 -YW-T09);the Key Directional Project of the Chinese Academy of Sciences and the National Natural Science Foundation of China(Grant Nos.10173020,10673021,10778631 and 10903019)

摘　　要：Once the energies of electrons near the Fermi surface obviously exceed the threshold energy of the inverse β decay,electron capture（EC） dominates inside the magnetar.Since the maximal binding energy of the 3 P 2 neutron Cooper pair is only about 0.048 MeV,the outgoing high-energy neutrons（E k（n） 60 MeV） created by the EC can easily destroy the 3 P 2 neutron Cooper pairs through the interaction of nuclear force.In the anisotropic neutron superfluid,each 3 P 2 neutron Cooper pair has magnetic energy 2μ n B in the applied magnetic field B,where μ n = 0.966 × 10 23 erg.G 1 is the absolute value of the neutron abnormal magnetic moment.While being destroyed by the high-energy EC neutrons,the magnetic moments of the 3 P 2 Cooper pairs are no longer arranged in the paramagnetic direction,and the magnetic energy is released.This released energy can be transformed into thermal energy.Only a small fraction of the generated thermal energy is transported from the interior to the surface by conduction,and then it is radiated in the form of thermal photons from the surface.After highly efficient modulation within the star＇s magnetosphere,the thermal surface emission is shaped into a spectrum of soft X-rays/γ-rays with the observed characteristics of magnetars.By introducing related parameters,we calculate the theoretical luminosities of magnetars.The calculation results agree well with the observed parameters of magnetars.Once the energies of electrons near the Fermi surface obviously exceed the threshold energy of the inverse β decay,electron capture（EC） dominates inside the magnetar.Since the maximal binding energy of the 3 P 2 neutron Cooper pair is only about 0.048 MeV,the outgoing high-energy neutrons（E k（n） 60 MeV） created by the EC can easily destroy the 3 P 2 neutron Cooper pairs through the interaction of nuclear force.In the anisotropic neutron superfluid,each 3 P 2 neutron Cooper pair has magnetic energy 2μ n B in the applied magnetic field B,where μ n = 0.966 × 10 23 erg.G 1 is the absolute value of the neutron abnormal magnetic moment.While being destroyed by the high-energy EC neutrons,the magnetic moments of the 3 P 2 Cooper pairs are no longer arranged in the paramagnetic direction,and the magnetic energy is released.This released energy can be transformed into thermal energy.Only a small fraction of the generated thermal energy is transported from the interior to the surface by conduction,and then it is radiated in the form of thermal photons from the surface.After highly efficient modulation within the star＇s magnetosphere,the thermal surface emission is shaped into a spectrum of soft X-rays/γ-rays with the observed characteristics of magnetars.By introducing related parameters,we calculate the theoretical luminosities of magnetars.The calculation results agree well with the observed parameters of magnetars.

关 键 词：Landau levels Fermi surface thermal radiation heat conduction 

分 类 号：O482.5[理学—固体物理]